Slim to none.
Speaking as a black, Cosby has enough money and clout not to have to worry what anyone in the black community says about his being a race traitor or Uncle Tom for endorsing a Republican president.
However, so many blacks, even if they agree with the Republican platform on every point, just can't bring themselves to publicly identify with what they perceive to be the party of the oppressor.
It would be great if Cosby would come over to the 'dark side,' but he won't, even if he is increasingly sounding like Darth Vader, if you get my drift.